1. Field of the Invention
This invention relates to new and improved apparatus for guiding welding torches, slaves and the like, and the new and improved electronic circuitry by which a probe or guide controls its own travel, and in turn controls and causes the travel of a welding torch, slave, and the like subsequently to trace the travel of the guide or probe, whether on a two or three-dimensional path, and including vertical and horizontal variations therein.
2. Description of the Prior Art
Automatic welding apparatus is well known; in addition, guiding systems wherein a guide or probe provides an electrical signal for actuating a welding torch to move the torch in a predetermined direction in a predetermined space for as long as the signal is sent, substantially simultaneously with the signal and the movement or deviations of the guide or probe, are well known in the art.
In such systems, the probe, carried upon horizontal and vertical cross-slides or other positioning apparatus, is biased against predetermined vertical and/or horizontal surfaces, and responds to deviations in the surfaces in order to close circuits and originate signals which cause drive means to move the welding torch, carried upon similar positioning apparatus, a distance corresponding to the change in path of the probe caused by the deviation. Thus, the welding torch substantially duplicates the path of the probe so as to lay down a welding bead which follows the surfaces against which the probe is biased. However, the path of the torch is generally spaced from the deviation either (1) by the lineal distance between the probe and the torch, i.e., by the distance the probe and torch are separated from each other with respect to the basic direction of travel of the entire apparatus, or (2) by a distance dependent upon the effect of the time lag in initiating torch movement due to the inertia of the system. To this latter condition, there is added a further effect of the distance between the probe and guide, whether mounted on its own slide carried on the torch, or mounted on a separate cross-slide. This lack of one-to-one correspondence with the guide path means that deviations are often corrected for by the torch either before or after they are reached during the travel of the torch, and when reached, are ignored; therefore, the bead does not in fact follow the surface traced by the probe, and so fails to make the desired perfect weld.